Optical film

ABSTRACT

An optical film which comprises a transparent resin layer ( 1 ) made of a photo-curable resin having a self-healing property, an antireflection layer ( 2 ) present on one side of the transparent resin layer ( 1 ), and a color tone correcting layer ( 3 ) containing a colorant which has a color tone correcting property, present on the other side of the transparent resin layer ( 1 ) opposite from the antireflection layer ( 2 ).

This application is a Divisional application of U.S. Ser. No. 10/176,683filed Jun. 24, 2002, now allowed.

The present invention relates to an optical film having anantireflection property and having an optical correcting property suchas a color tone correcting property or a near infrared ray absorptionproperty, and a process for producing it.

For various displays such as a cathode-ray tube (CRT), a visual displayterminal (VDT), a liquid crystal display (LCD), a plasma display(hereinafter referred to as PDP) and the like, an antireflection filmhas conventionally been provided on a display surface in order toimprove the visibility. Further, not only for the displays, but also forvarious optical articles such as windows of architectural structures orvehicles, an antireflection film may be used in some cases.

Such an antireflection film is usually provided as an outermost layer ofe.g. an optical article, and consequently tends to get externalscratches. Optical properties of the film will change if the externalscratches remain, and therefore it is important for the antireflectionfilm to have good scratch resistance.

Further, especially for displays which are likely to emitelectromagnetic waves from a display, such as PDP, it is requested toshield near infrared rays as heat radiation which are likely to generatea noise for an electronic equipment, on the viewer's side of thedisplay, and for example, {circle around (1)} JP-A-10-219006 proposes anoptical film comprising a polyurethane resin layer and a thin film layerhaving an antireflection property, and having an infrared ray absorptionproperty imparted thereto. In {circle around (1)}, an infrared rayabsorbent is contained either in a polyurethane resin layer or inanother synthetic resin layer.

The polyurethane resin layer in {circle around (1)} is made of athermoplastic polyurethane resin or a thermosetting polyurethane resin,which is transparent and has a self-healing property and scratchresistance, and by providing an antireflection thin layer thereon, anantireflection film excellent in scratch resistance can be obtained.

However, there has been a problem such that it takes relatively longtime to form a layer made of thermoplastic or thermosetting polyurethaneresin, whereby the productivity tends to be poor.

Further, {circle around (2)} JP-A-2000-249804 discloses anantireflection substrate comprising a transparent cured layer of aphoto-curable resin and a low refractive index layer to impart anantireflection property laminated on the transparent layer.

In {circle around (2)}, the transparent cured layer made of aphoto-curable resin can be formed by a simple and highly productivemethod, and an antireflection substrate excellent in scratch resistancecan be obtained with high productivity.

By the way, for optical articles performing a color display such ascolor PDP, in order to improve the image quality, a color tonecorrection of a visible light emitted from a screen is requested in somecases. The color tone correction of a visible light can be carried out,for example, by letting a light be transmitted through a coloredtransparent layer having a property of selectively absorbing a light ina specific wavelength region. Further, as mentioned above, it isrequested to shield near infrared rays on the viewer's side of a displayin some cases depending on the property of the display.

The above {circle around (2)} discloses that e.g. a near infrared rayabsorbent or a colorant may be mixed in the photo-curable resin.

However, it was found that even by incorporating a near infrared rayabsorbent or a colorant such as a coloring agent into the transparentcured layer of the photo-curable resin to impart a near infrared rayabsorption property or a color tone correcting property as disclosed in{circle around (2)}, the colorant may be deteriorated by irradiationwith ultraviolet rays for curing the photo-curable resin, therefore nodesired optical correcting property can appropriately be obtained.

Further, it was also found that a shield of ultraviolet ray shielding bythe colorant in the photo-curable resin occurs, and consequently, thecuring of the photo-curable resin by irradiation with ultraviolet raysis less likely to proceed, and it becomes necessary to increase the doseof the irradiation with ultraviolet rays, which decreases the productionefficiency.

Under these circumstances, the present invention has been made toovercome the above problems, and it is an object of the presentinvention to provide an optical film having an antireflection propertyand having an optical correcting property such as a color tonecorrecting property or a near infrared ray absorption property, andbeing excellent in productivity, and a process for producing it.

The present inventors have conducted extensive studies on the cause ofthe deterioration of the colorant by irradiation with ultraviolet rays,and as a result, found that a radical generated in the photo-curableresin at the time of the irradiation with ultraviolet rays is a majorfactor of the deterioration of the colorant. They have further foundthat if the colorant exists without being in contact with thephoto-curable resin, the deterioration of the colorant at the time ofthe irradiation with ultraviolet rays can be prevented and the curing ofthe photo-curable resin is not inhibited. The present invention has beenaccomplished on the basis of these discoveries.

Namely, the optical film of the present invention comprises atransparent resin layer (1) made of a photo-curable resin having aself-healing property, an antireflection layer (2) present on one sideof the transparent resin layer (1), and a color tone correcting layer(3) containing a colorant which has a color tone correcting property,present on the other side of the transparent resin layer (1) oppositefrom the antireflection layer (2).

With respect to the optical film of the present invention, thetransparent resin layer (1) made of a photo-curable resin can be curedrapidly by irradiation with ultraviolet rays, and accordingly productionof the transparent resin layer (1) can be performed simply with goodproductivity.

Further, no colorant for color tone correction is contained in thetransparent resin layer (1) made of a photo-curable resin, and the colortone correcting layer (3) is provided separately from the transparentresin layer (1), whereby the deterioration of the colorant by a radicalgenerated in the transparent resin layer (1) at the time of theirradiation with ultraviolet rays, can be prevented, and the inhibitionof curing of the photo-curable resin by the colorant is also prevented.

Further, since the transparent resin layer (1) as an underlayer of theantireflection layer (2), is made of a photo-curable resin having aself-healing property, the surface of the antireflection layer (2) isless likely to be scratched, and an excellent scratch resistance can beobtained.

Further, since the antireflection layer (2) and the color tonecorrecting layer (3) are united with the transparent resin layer (1)sandwiched therebetween, both of an antireflection property and anoptical correcting property can be obtained, good handling efficiencycan be obtained and the mounting and processing can be performed easily.

In the present invention, in the color tone correcting layer (3), acolorant which has a near infrared ray absorption property may becontained in addition to the colorant which has a color tone correctingproperty. With such a construction, an optical film having both aproperty of correcting the color tone of visible light and a property ofabsorbing near infrared rays, can be obtained.

In the present invention, the antireflection layer (2) is preferablymade of a non-crystalline fluoropolymer. The non-crystallinefluoropolymer has a low refractive index, a high transparency and anexcellent antireflection property, and by providing a layer made of thismaterial on the transparent resin layer (1) having a self-healingproperty, a good scratch resistance can also be obtained.

The non-crystalline fluoropolymer is preferably a polymer having afluorine-containing alicyclic structure.

In the present invention, it is preferred to provide an interlayerhaving a refractive index higher than that of the transparent resinlayer (1), between the transparent resin layer (1) and theantireflection layer (2), whereby the antireflection property mayfurther be improved.

The interlayer is preferably one member selected from the groupconsisting of a layer made of a resin having a refractive index higherthan the refractive index of the transparent resin layer, a layer madeof a metal oxide having a refractive index higher than the refractiveindex of the transparent resin layer, and a layer containing a metaloxide having a refractive index higher than the refractive index of thetransparent resin layer.

The process for producing the optical film of the present inventioncomprises laminating, on a transparent substrate, a color tonecorrecting layer (3) containing a colorant which has a color tonecorrecting property, a transparent resin layer (1) made of aphoto-curable resin having a self-healing property, and anantireflection layer (2), in this order.

By laminating an interlayer and the antireflection layer (2) in thisorder on the transparent resin layer (1), an optical film having aninterlayer can be produced.

Otherwise, the process for producing the optical film of the presentinvention comprises laminating on one side of a transparent substrate, atransparent resin layer (1) made of a photo-curable resin having aself-healing property, and an antireflection layer (2) in this order,and forming a color tone correcting layer (3) containing a colorantwhich has a color tone correcting property on the other side of thetransparent substrate.

By laminating an interlayer and the antireflection layer (2) in thisorder on the transparent resin layer (1), an optical film having aninterlayer can be produced.

In the accompanying drawing:

FIG. 1 is a schematic sectional view illustrating a substantial part ofone embodiment of the optical film of the present invention.

The optical film 10 of the present embodiment comprises a transparentresin layer 1, an antireflection layer 2 provided on one side of thetransparent resin layer 1, and a color tone correcting layer 3 providedon the other side of the transparent resin layer 1 opposite from theantireflection layer 2.

Now, the detail will be explained about each layer.

Transparent Resin Layer

In the present invention, the transparent resin layer 1 is made of aphoto-curable resin having a self-healing property.

In the present invention, having a self-healing property means that “avalue of the maximum load measured by a HEIDON scratch tester, withwhich scratches formed by using as a scratcher a diamond chip having atip diameter of 15 μm at 23° C. in a relative humidity of 50%, candisappear” (hereinafter referred to as a self-healing degree) is atleast 10 g. The self-healing degree of the transparent resin layer 1 inthe present invention is preferably at least 30 g.

Further, the transparent resin layer 1 of the present invention has atensile stress at an elongation of 10%, measured in accordance with atensile test method based on JIS K7127 at 23° C. in a relative humidityof 50%, of preferably at least 2 MPa from the viewpoint of having asufficient strength for practical use, preferably not exceeding 30 MPafrom the viewpoint of having a sufficient self-healing property. Thetensile stress is particularly preferably from 2 to 20 MPa.

In order to exhibit sufficient self-healing property of the transparentresin layer 1, the thickness of the transparent resin layer 1 ispreferably at least 10 μm, and in order to conduct photo-curingefficiently, it is preferably at most 1,000 μm. It is particularlypreferably from 20 to 500 μm.

The photo-curable resin constituting the transparent resin layer 1 ofthe present invention, is a composition containing a photopolymerizablemonomer and a photoinitiator as essential components, and undergoescuring by irradiation with electromagnetic waves such as ultravioletrays to form a cured product having a self-healing property.

The photoinitiator is a material which gets excited by absorbing a lightenergy, and generates a radical to initiate the polymerization reactionof the photopolymerizable monomer.

As a polymerization reaction site of the photopolymerizable monomer,e.g. an acryloyl group, a methacryloyl group, a vinyl group, an allylgroup, a mercapto group or an amino group may be mentioned.Particularly, an acryloyl group and a methacryloyl group have highreactivity and are preferred.

Specific examples of the photopolymerizable monomer include unsaturatedpolyester, epoxy acrylate, urethane acrylate, polyester acrylate, alkydacrylate, silicone acrylate, polyene/polythiol type spiran, amino alkyd,hydroxyethyl acrylate and vinyl ether. Among them, particularly onehaving a low shrinkage ratio at the time of the curing is preferred,specifically, urethane acrylate is preferred. These monomers may be usedas a mixture of two or more of them.

As the urethane acrylate, one made from a non-yellowing polyisocyanatecompound is preferred. As the non-yellowing polyisocyanate,4,4′-methylenebis(cyclohexyl isocyanate), isophorone diisocyanate,cyclohexane diisocyanate, tetramethylene diisocyanate, hexamethylenediisocyanate, for example, may be mentioned.

In the present invention, the curing shrinkage ratio of the transparentresin layer 1 is preferably less than 10%, and more preferably at most8%. If the cure shrinkage ratio is less than 10%, no warpage tends to beformed on the optical film 10, and particularly when the optical film isused as stuck to a display surface of various displays or other parts,the handling for sticking become efficient.

Here, the cure shrinkage ratio is a value expressed by {((density aftercuring)−(density before curing))/(density before curing)}×100 (%).

As the photoinitiator, a cleavage type photoinitiator such as benzoinether, 1-hydroxycyclohexyl phenyl ketone,2-methyl-1-(4-(methylthio)phenyl)-2-morpholinopropane-1-one or2,2-dimethoxy-1,2-diphenylethane-1-one, a hydrogen plucking typephotoinitiator such as benzophenone, thioxanthone, xanthone,2-chlorothioxanthone, Michler's ketone, 2-isopropylthioxanthone, benzyl,9,10-phenanthrenequinone or 9,10-anthraquionone may, for example, bementioned. These photoinitiators may be used as a mixture of two or moreof them as the case requires.

The amount of the photoinitiator to be incorporated is determined by thetype of the photopolymerizable monomer and the thickness of thetransparent resin layer 1, and is preferably from 0.1 to 10 parts byweight per 100 parts by weight of the total amount of thephotopolymerizable monomer. Further, in order to impart additionalproperties to the photo-curable resin, a light stabilizer, anantioxidant, an ultraviolet ray absorbent, an antistatic agent or thelike may be mixed in the photo-curable resin to the extent of notpreventing the curing and not deteriorating the elasticity.

The method for preparing the photo-curable resin is preferably such thata photopolymerizable monomer and a photoinitiator are mixed and stirredat a temperature at which no gelation takes place, until a uniformsolution is formed.

A light source to cure the photo-curable resin may be any device capableof generating a wavelength contributing to the curing reactionefficiently, such as a low pressure mercury lamp, a high pressuremercury lamp, a super high pressure mercury lamp, a metal halide lamp,an ultraviolet laser, an electrodeless discharge lamp or an electronbeam.

The method to form the transparent resin layer 1 may, for example, be amethod of coating a support by means of a coating method such as dipcoating, roll coating, spray coating, gravure coating, comma coating ordie coating, followed by curing by irradiation with ultraviolet rays.Further, a method of covering the coated surface coated by any of theabove methods, with a covering material having a smooth releasingsurface and having a good transparency to the light for irradiation suchas ultraviolet rays, so that the smooth releasing surface of thecovering material contacts with the coated surface, followed byirradiation with a light such as ultraviolet rays for curing, may alsobe used. The latter method is a preferred method, since an unfavorableeffect on the curing due to oxygen or water in the air can be inhibitedat the time of the photo-curing, and a transparent resin layer 1 havinga smooth surface can be obtained as well. The light such as ultravioletrays may be irradiated through the covering material or from the otherside of the covering material. The covering material may be any materialso long as it has good transparency to the light for irradiation, andhaving a smooth releasing surface, and is preferably a film made of atransparent polymer material, at least one side of which not subjectedto an adhesion facilitating treatment, or at least one side of whichsubjected to a release treatment. For example, a polyester type film, apolyacryl type film, a cellulose type film, a polyether sulfone film ora polycarbonate film may, for example, be mentioned, but the film is notlimited thereto. Particularly, a polyester type film, one side of whichnot subjected to adhesion facilitating treatment, is preferred. As apolyester type film, a polyethylene terephthalate film is particularlypreferred. By the above-mentioned coating methods, continuous processingis possible, whereby the productivity is excellent as compared with e.g.a batch type vapor deposition method. Particularly, die coating ispreferred since it is excellent in continuous productivity and capableof forming a large size film, the film thickness deviation is small, andit can easily be applied to from small scale to large scale.

Further, an antiglare layer may be formed on the surface of thetransparent resin layer 1 by a method of incorporating particles of e.g.a silica sol into the photo-curable resin constituting the transparentresin layer 1, or a method of subjecting the surface of the transparentresin layer 1 to embossing. An antiglare layer may be formed also bylaminating on the transparent resin layer, another transparent layercontaining particles of e.g. a silica sol.

Antireflection Layer

As a material for forming the antireflection layer 2, a transparentmaterial having a refractive index lower than that of the transparentresin layer 1, is preferably used. In the present invention, therefractive index of the transparent resin layer 1 is preferably from1.45 to 1.55, and the refractive index of the antireflection layer 2 ispreferably at most 1.36. The difference in the refractive index betweenthe transparent resin layer 1 and the antireflection layer 2 ispreferably from 0.09 to 0.19.

The thickness of the antireflection layer 2 is, in order to obtain asufficient antireflection effect, from 10 to 500 nm, preferably from 30to 300 nm, more preferably from 50 to 200 nm.

In the present invention, as a material for the antireflection layer 2,a non-crystalline fluoropolymer is preferably used. The non-crystallinefluoropolymer is free from light scattering by crystals and is excellentin transparency.

As the non-crystalline fluoropolymer, {circle around (1)} a polymerhaving a fluorine-containing alicyclic structure on its main chain,obtained by polymerizing a fluorine-containing monomer having analicyclic structure, or {circle around (2)} a polymer having afluorine-containing alicyclic structure on its main chain, obtained bycyclic polymerization of a fluorine-containing monomer having at leasttwo polymerizable double bonds, are preferred.

Having a fluorine-containing alicyclic structure on its main chain meanshaving a structure wherein at least one carbon atom constituting thealiphatic ring is a carbon atom in the carbon chain constituting themain chain, and a fluorine atom or a fluorine-containing group isconnected to at least a part of carbon atoms constituting the aliphaticring.

The polymer {circle around (1)} having a fluorine-containing alicyclicstructure on its main chain, which is obtained by polymerizing a monomerhaving a fluorine-containing ring structure, is known from e.g.JP-B-63-18964. Namely, it may, for example, be a homopolymer of amonomer having a fluorine-containing alicyclic structure such asperfluoro(2,2-dimethyl-1,3-dioxol), or a copolymer of said monomer witha radical polymerizable monomer such as tetrafluoroethylene.

The polymer {circle around (2)} having a fluorine-containing alicyclicstructure on its main chain, which is obtained by cyclic polymerizationof a fluorine-containing monomer having at least two polymerizabledouble bonds, is known from e.g. JP-A-63-238111 and JP-A-63-238115.Namely, it may, for example, be a polymer obtained by cyclicpolymerization of a fluorine-containing monomer having at least twopolymerizable double bonds such as perfluoro(allyl vinyl ether) orperfluoro(butenyl vinyl ether), or a copolymer of a fluorine-containingmonomer having at least two polymerizable double bonds with a radicalpolymerizable monomer such as tetrafluoroethylene.

Or, it may be a polymer obtained by copolymerizing a monomer having afluorine-containing alicyclic structure such asperfluoro(2,2-dimethyl-1,3-dioxol) with a fluorine-containing monomerhaving at least two polymerizable double bonds such as perfluoro(allylvinyl ether) or perfluoro(butenyl vinyl ether).

As the polymer having a fluorine-containing alicyclic structure, apolymer having a fluorine-containing alicyclic structure on its mainchain is suitable, and preferred is one containing at least 20 mol % ofmonomer units having a fluorine-containing alicyclic structure in themonomer units constituting the polymer, from the viewpoint oftransparency and mechanical properties.

The polymer having a fluorine-containing alicyclic structure ispreferably one having on its terminal a reactive group which may undergochemical bonding or anchor bonding with a material for a layer under theantireflection layer. Such a reactive group may, for example, be ahydroxyl group, a carboxyl acid group, an amino group, an epoxy group,an acryloyl group, a methacryloyl group, an isocyanate group, a cyanogroup, a carbamoyl group, a mercapto group or a vinyl group.

The polymer having a fluorine-containing alicyclic structure on its mainchain may be commercially available as “CYTOP” (tradename) manufacturedby Asahi Glass Company, Limited, and any known fluoropolymer may be usedin the present invention.

Here, in the present invention, in order to increase the adhesionbetween the transparent resin layer 1 and the antireflection layer 2, 1)an adhesive layer may be provided between the above layers, or 2) anadditive for strengthening adhesion may be added to the antireflectionlayer 2. With respect to the above item 1), the thickness of theadhesive layer is preferably from 1 to 50 nm so as not to deteriate theoptical properties of the optical film 10 of the present invention, andwith respect to the above item 2), the amount of the additive ispreferably at most 50 parts by mass per 100 parts by mass of thenon-crystalline fluoropolymer which forms the antireflection layer 2,from the same reason as mentioned above. As a material constituting theadhesive layer or additive, the following alkoxysilanes may bementioned, and they may be used alone or in combination as a mixture oftwo or more of them:

Monoalkoxysilanes such as vinyltriethoxysilane, trimethylmethoxysilane,trimethylethoxysilane, dimethylvinylmethoxysilane anddimethylvinylethoxysilane; dialkoxysilanes such asγ-chloropropylmethyldimethoxysilane, γ-chloropropylmethyldiethoxysilane,γ-aminopropylmethyldiethoxysilane, γ-aminopropylmethyldimethoxysilane,N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane,N-β-(aminoethyl)-γ-aminopropylmethyldiethoxysilane,γ-glycidyloxypropylmethyldimethoxysilane,γ-glycidyloxypropylmethyldiethoxysilane,γ-methacryloxypropylmethyldimethoxysilane, methyldimethoxysilane,methyldiethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane,methylvinyldimethoxysilane, methylvinyldiethoxysilane,diphenyldimethoxysilane, diphenyldiethoxysilane,3,3,3-trifluoropropylmethyldimethoxysilane,3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctylmethyldimethoxysilane and3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecylmethyldimethoxysilane;and tri- or tetra-alkoxysilanes such as γ-aminopropyltrimethoxysilane,γ-aminopropyltriethoxysilane,N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane,N-β-(aminoethyl)-γ-aminopropyltriethoxysilane,γ-mercaptopropyltrimethoxysilane, γ-glycidyloxypropyltrimethoxysilane,γ-glycidyloxypropyltriethoxysilane,γ-methacryloxypropyltrimethoxysilane, γ-chloropropyltrimethoxysilane,methyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane,3,3,3-trifluoropropyltrimethoxysilane,3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyltrimethoxysilane,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecyltrimethoxysilane,tetramethoxysilane and tetraethoxysilane.

As particularly preferred ones which improve the adhesiveness to thetransparent resin layer 1 without impairing the transparency of theantireflection layer 2, the following may be mentioned:

γ-aminopropyltriethoxysilane, γ-aminopropylmethyldiethoxysilane,γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldimethoxysilane,N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane,N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane,N-β-(aminoethyl)-γ-aminopropyltriethoxysilane andN-β-(aminoethyl)-γ-aminopropylmethyldiethoxysilane;γ-glycidyloxypropyltrimethoxysilane,γ-glycidyloxypropylmethyldimethoxysilane,γ-glycidyloxypropyltriethoxysilane andγ-glycidyloxypropylmethyldiethoxysilane, having an epoxy group.

Further, the surface of the antireflection layer 2 as an outermost layermay be coated with a lubricant to impart abrasion resistance within arange of not impairing the antireflection property, or a lubricant maybe incorporated into the antireflection layer 2. Such a lubricant may,for example, be a perfluoropolyether such as Krytox, tradename,manufactured by DuPont Inc., DEMNUM, tradename, manufactured by DaikinIndustries, Ltd., DAIFLOIL, tradename, manufactured by DaikinIndustries, Ltd., Fomblin, tradename, manufactured by Ausimont Inc.,FLONLUBE, tradename, manufactured by Asahi Glass Company, Limited.

The method for forming the antireflection layer 2 is not particularlylimited, and any optional forming method may be selected. For example, apolymer having a fluorine-containing alicyclic structure is soluble in afluorine type solvent such as perfluorooctane, CF₃(CF₂)_(n)CH═CH₂(wherein n is an integer of from 5 to 11), CF₃(CF₂)_(m)CH₂CH₃ (wherein mis an integer of from 5 to 11) or a fluorine-containing ether, and bycoating with a solution of this polymer by an appropriate coatingmethod, a desired thickness can easily be obtained.

Color Tone Correcting Layer

In the present invention, the color tone correcting layer 3 contains atleast a colorant which has a color tone correcting property, and mayfurther contain a colorant which has a near infrared ray absorptionproperty. The colorant may be either a dye or a pigment.

The thickness of the color tone correcting layer 3 is, in order toobtain an adequate optical correcting property, preferably from 0.1 to50 μm, and more preferably from 0.1 to 20 μm.

The color tone correcting layer 3 is preferably made of a materialcomprising a thermoplastic resin which is soluble in a solvent as themain component and having a colorant which has a color tone correctingproperty incorporated into the main component, or having a colorantwhich has a near infrared ray absorption property and a colorant whichhas a color tone correcting property incorporated into the maincomponent.

As the thermoplastic resin as the main component of the color tonecorrecting layer 3, for example, a polyester type resin, an olefin typeresin, a polyurethane type resin or the like may be used.

The colorant which has a color tone correcting property is used toselectively absorb part of a visible light in a specific wavelengthregion depending upon the purpose of use of the optical film 10, toimprove the color tone of the transmitted visible light. Such a coloranthaving a color tone correcting property is preferably one having anarrow absorption band in the visible light region and a hightransmittance in the other wavelength regions. Specifically, a knownorganic pigment, organic dye or inorganic pigment of azo type, condensedazo type, diimmonium type, phthalocyanine type, anthraquinone type,indigo type, perinone type, perylene type, dioxazine type, quinacridontype, methine type, isoindolinone type, quinophthalone type, pyrroletype, thioindigo type or metal complex type, may, for example, bementioned. Preferred is a colorant having favorable weather resistanceand having favorable compatibility or dispersibility with the maincomponent in the color tone correcting layer 3, such as a diimmoniumtype, phthalocyanine type or anthraquinone type colorant, and they maybe used alone or in combination as a mixture of at least two.

The colorant which has a near infrared ray absorption property may, forexample, be a polymethine type, phthalocyanine type, metal complex type,aminium type, imonium type, diimonium type, anthraquinone type, dithiolmetal complex type, naphthoquinone type, indolephenol type, azo type ortriallylmethane type compound, but is not limited thereto. For thepurpose of absorbing heat radiation and preventing noises of anelectronic equipment, preferred is a near infrared ray absorbent havinga maximum absorption wavelength of from 750 to 1,100 nm, andparticularly preferred is a metal complex type, aminium type ordiimonium type compound. The near infrared ray absorbent may be usedalone or in combination as a mixture of at least two.

When the optical film 10 is used as a film for antireflection andoptical correction for image display devices particularly for PDPs, intothe color tone correcting layer 3, one type or plural types of colorantsare preferably incorporated so as to selectively absorb and decay extraluminescent color (mainly in a wavelength region of from 560 to 610 nm)from a discharge gas sealed in the main body of PDP, such as a twocomponent gas comprising neon and xenon. By such a colorantconstruction, of the visible light emitted from the PDP, extra lightresulting from light emission of a discharge gas is absorbed in anddecayed by the color tone correcting layer 3, and as a result, a displaycolor of visible light emitted from the PDP can be made close to theaimed display color, whereby a PDP device capable of displaying naturalcolor tones can be provided. Further, when a colorant which has a nearinfrared ray absorption property is contained in the color tonecorrecting layer 3, near infrared rays emitted from the PDP are absorbedin the color tone correcting layer 3, whereby the noise against anelectric equipment can be prevented.

The amount of the colorant incorporated in the color tone correctinglayer 3 is, from the viewpoint of providing a sufficient opticalcorrecting property, preferably at least 0.1 mass % in total based onthe thermoplastic resin as the main component of the color tonecorrecting layer 3, and from the viewpoint of ensuring the durabilityand weather resistance of the colorant, preferably at most 20 mass % intotal based on the thermoplastic resin as the main component of thecolor tone correcting layer 3. It is more preferably from 0.1 to 10 mass%.

The solvent in which the resin as the main component is dissolved may,for example, be a ketone type solvent such as cyclopentanone orcyclohexanone, an ether type solvent, an ester type solvent such asbutyl acetate, an ether alcohol type solvent such as ethyl cellosolve, aketone alcohol type solvent such as diacetone alcohol or an aromaticsolvent such as toluene. They may be used alone or as a mixed solventsystem comprising at least two types mixed.

The method of forming the color tone correcting layer 3 is notparticularly limited. For example, a substrate is coated with a coatingliquid obtained by dissolving the main component and the colorant in asolvent, followed by drying, whereby a color tone correcting layer 3 ina desired thickness can be formed. As the coating method, dip coating,roll coating, spray coating, gravure coating, comma coating or diecoating may, for example, be selected. By these coating methods,continuous processing is possible, whereby the productivity is excellentas compared with e.g. a vapor deposition method of batch type. Spincoating by which a thin uniform coating film can be formed can also beemployed.

Production Process of Optical Film

The optical film 10 according to the present embodiment may be formed insuch a manner that on a transparent substrate (not shown), the colortone correcting layer 3, the transparent resin layer 1 and theantireflection layer 2 are laminated in this order to form the opticalfilm 10 integrated with the transparent substrate. Or, it may be formedin such a manner that on one side of the transparent substrate, thetransparent resin layer 1 and the antireflection layer 2 are laminatedin this order and the color tone correcting layer 3 is formed on theother side of the transparent substrate to form the optical film 10integrated with the transparent substrate. In this case, it is alsopossible to form the color tone correcting layer 3 first and then tolaminate the transparent resin layer 1 and the antireflection layer 2 inthis order on the other side of the transparent substrate. Thetransparent substrate is preferably a film or a sheet which istransparent and which does not deteriorate the optical property. Thetransparent substrate may, for example, be a polyethylene terephthalatefilm, a polycarbonate film, a polymethylmethacrylate film,triacetylcellulose film or a glass sheet.

Otherwise, the optical film may also be formed in such a manner that onan appropriate substrate, preferably on a substrate with a releasingsurface, the color tone correcting layer 3, the transparent resin layer1 and the antireflection layer 2 are laminated in this order, then theoptical film 10 comprising those three layers is separated from thesubstrate.

In order to strengthen the adhesion between the transparent resin layer1 and the antireflection layer 2, prior to the formation of theantireflection layer 2, it is effective to apply an active energy raytreatment such as a corona discharge treatment or an ultraviolet raytreatment, or a treatment with a primer, to the surface of thetransparent resin layer 1.

Use of Optical Film

The optical film 10 can be used as a film-like optical article as it is,or used as a component of an image display device as stuck to a displaysurface. It may also be used as a component of a touch panel for animage display device, as stuck to a display surface. Further, theoptical film 10 can constitute an optical filter for an image displaydevice, as it is or as laminated with another transparent substrate. Theimage display device may, for example, be PDP, a cathode ray tube (CRT),a visual display terminal (VDT), a liquid crystal display (LCD), a lightemission display (LED), an electrochromic display (ECD), anelectroluminescence panel or a projection display.

It may be used as stuck to another film-like optical article, or may beused as stuck to a window material. Said another film-like opticalarticle may, for example, be a polarizing film, a light diffusion film,a phase difference film, a Fresnel lens film, a prism lens film or alenticular film. The window material may, for example, be one forarchitectural structures or one for vehicles.

The method to stick the optical film 10 to such an optical article isnot particularly limited, and a method such as adhesion bonding,sticking or heat such as gluing, adhesion, heat sealing may be selected.A tackifying layer may preliminarily be prepared on the color tonecorrecting layer 3 of the optical film 10 or, if the transparentsubstrate (not shown) is integrated with the color tone correcting layer3, on the transparent substrate.

By applying the optical film 10 to an optical filter for an imagedisplay device, such effects that the reflection of outside light on thedisplay surface is prevented by the antireflection layer 2, thebrightness is improved, and the contrast is improved, can be obtained.Further, by the color tone correcting layer 3, it is possible to shieldnear infrared rays emitted from the display, or to improve the imagequality by conducting color tone correction of visible light. Further,the optical film 10 contributes to improvement of the strength of thedisplay surface and prevention of the scattering. Particularly, theoptical film 10 has a high accuracy of optical correction since thedeterioration of the colorant is suppressed during the productionprocess, and has also an advantage in cost because it has a goodproductivity.

By applying the optical film 10 to a touch panel for an image displaydevice, an antireflection property, a color tone changing property forvisible light, a near infrared ray absorption property, a protectioneffect of the display surface and the like can be obtained, and besides,since particularly the transparent resin layer 1 has a self-healingproperty and has relatively high flexibility and elasticity, a touchpanel using this will be one providing good feeling at the time ofinputting with a finger or with a pen.

By applying the optical film 10 to various window materials for e.g.architectural structures or vehicles, it is possible to impart anantireflection property, a color tone changing property for visiblelight, a near infrared ray absorption property and the like to thewindow materials.

Other Preferred Embodiment

By providing an interlayer (not shown) having a refractive index higherthan that of the transparent resin layer 1 between the transparent resinlayer 1 and the antireflection layer 2, more excellent antireflectioneffect can be obtained.

The refractive index of the interlayer is preferably from 1.55 to 1.65.The difference in the refractive index between the interlayer and theantireflection layer 2 is preferably from 0.19 to 0.29. Further, thedifference in the refractive index between the interlayer and thetransparent resin layer 1 is preferably from 0.01. to 0.2, morepreferably from 0.01 to 0.1.

The thickness of the interlayer is, in order to obtain a sufficienteffect to improve the antireflection property by providing theinterlayer, preferably at least 50 nm, and in order to obtain asufficient effect to improve the scratch resistance of theantireflection layer 2 by providing the transparent resin layer 1 havinga self-healing property underneath the antireflection layer 2,preferably at most 500 nm. It is particularly preferably at most 300 nm.

The interlayer is preferably a layer made of a resin having a refractiveindex higher than the refractive index of the transparent resin layer, alayer made of a metal oxide having a refractive index higher than therefractive index of the transparent resin layer, or a layer containing ametal oxide having a refractive index higher than the refractive indexof the transparent resin layer.

The resin having a high refractive index is preferably a polymer havingan aromatic ring on its main chain or side chains, such as polystyrene,poly(2-chlorostyrene), poly(2,6-dichlorostyrene), poly(2-bromostyrene),poly(2,6-dibromostyrene), polycarbonate, aromatic polyester,polysulfone, polyethersulfone, polyarylsulfone,poly(pentabromophenylmethacrylate), a phenoxy resin or its brominatedproduct, or an epoxy resin or its brominated product, or a polymercontaining e.g. a bromine or sulfur element. Further, it is possible toincrease the adhesive property to the transparent resin layer 1 or tothe antireflection layer 2, by modifying the terminal of such a resinwith a reactive functional group. Among the above resins, e.g. a phenoxyresin and an epoxy resin have active functional groups at the terminalswithout modification, and they are preferred from the viewpoint of theadhesive property.

As the metal oxide, particularly by using a metal oxide havingconductivity, the interlayer becomes one having conductivity, whereby anantistatic property can be imparted to the optical film 10. In a casewhere the antistatic property is required, the metal oxide preferablyhas a resistivity of from 1×10⁻⁷ to 1×10³ Ω·m.

The metal oxide may, for example, be Sb₂O₅, SnO₂, In₂O₃, TiO₂, RuO₂,Yb₂O₃, Ag₂O, CuO, or FeO, and, Sb₂O₅, SnO₂ and In₂O₃ having goodtransparency and film forming property are particularly preferred.Further, a layer made of a metal oxide and an oxide of an alloy of ametal such as Sb or Al, is also preferred, which further increasesconductivity.

It is also possible to incorporate the above-described resin having ahigh refractive index or the above-described resin for the transparentsubstrate into a layer made of a metal oxide in order to improve thefilm forming property, or to incorporate a compound having a functionalgroup which effectively functions for a chemical bonding such as anepoxy group, an amino group or a hydroxyl group into the layer in orderto impart adhesion.

As a method of forming the interlayer, it is preferred to coat thetransparent resin layer 1 with an organic solvent solution of a resinhaving a refractive index higher than the refractive index of thetransparent resin layer 1 in the same method as the coating inproduction of the transparent resin layer 1, whereby the film formationcost is low, the coating property is excellent, and the layer can beproduced stably.

Further, in order to strengthen the adhesion between the transparentresin layer 1 and the interlayer, it is effective to preliminarily applyan active energy ray treatment such as a corona discharge treatment oran ultraviolet ray treatment, or a treatment with a primer, to thesurface of the transparent resin layer 1.

Now, the present invention will be described in further detail withreference to Examples. However, it should be understood that the presentinvention is by no means restricted to such specific Examples.

EXAMPLE 1

(a) Formation of Color Tone Correcting Layer

A colorant liquid A as a material for a color tone correcting layer wasprepared as follows. Namely, a polyester resin for optical use (O-PET,tradename, manufactured by Kanebo Ltd.) as the main component, wasdissolved in cyclopentanone so that the resin concentration would be 10%to obtain a main component solution of a color tone correcting layer.

To 100 g of this main component solution, 0.063 g of a red dye (WaxlineRed MP-FW, tradename, manufactured by Avecia Ltd.) and 0.0729 g of ablue dye (Waxline Blue AP-FW, tradename, manufactured by Avecia Ltd.)were added, followed by stirring until those dyes were completelydissolved to obtain a colorant liquid A.

A transparent substrate made of a polyethylene terephthalate film havinga thickness of 100 μm was coated with the colorant liquid A by a barcoater so that the thickness of the dried coating film would be 2 μm,and made to pass through an oven having its temperature adjusted to 120°C. for 2 minutes so that the solvent was distilled off to form a colortone correcting layer.

(b) Formation of Transparent Resin Layer

A resin liquid B as a material for a transparent resin layer wasprepared as follows. Namely, 70 parts by mass of a non-yellowing typeurethane acrylate (UF-8001, tradename, manufactured by Kyoeisha ChemicalCo., Ltd.), 30 parts by mass of tripropylene glycol diacrylate (ARONIXM220, tradename, manufactured by Toagosei Co, Ltd.) and 3 parts by massof benzophenone were mixed to obtain a uniform resin liquid B.

The color tone correcting layer formed in the above-mentioned Step (a)was coated with the resin liquid B by a bar coater, followed byirradiation with ultraviolet rays with a dose of 600 mj/cm² by a highpressure mercury lamp (120 mW/cm², the distance from the light source tothe irradiated plane: 150 mm, line speed: 2.5 m/min) to form atransparent resin layer having a thickness of 0.2 mm without a tuck.

(c) Formation of Interlayer and Antireflection Layer

A corona discharge treatment was applied to the surface layer of thetransparent resin layer formed in the above-mentioned Step (b), and thesurface layer was spin-coated with a solution having a brominatedphenoxy resin (Phenotohto YPB-43C, tradename, manufactured by TohtoKasei Co., Ltd., molecular weight: 60,000, refractive index: 1.63)diluted to 2% with cyclohexane (coating condition: 500 rpm×10 sec and3,000 rpm×20 sec) to form an interlayer (refractive index: 1.60, filmthickness: about 100 nm).

Then, the interlayer was spin-coated with a solution having a solutionof a non-crystalline fluoropolymer (CTL-805A, tradename, manufactured byAsahi Glass Company, Limited) diluted to 2% with a solvent (CT-SOLV180,tradename, manufactured by Asahi Glass Company, Limited) (coatingcondition: 500 rpm×10 sec and 3,000 rpm×20 sec), followed by heating at140° C. for 10 minutes so that the solvent was distilled off to form anantireflection layer having a thickness of about 100 nm, to obtain anoptical film.

EXAMPLE 2

An optical film was produced in the same manner as in Example 1 exceptthat a different photo-curable resin to form a transparent resin layerwas used.

First, a color tone correcting layer was formed in the same manner as inStep (a) of Example 1.

Then, in order to form a transparent resin layer, 50 parts by mass of anon-yellowing type urethane acrylate (UF-503LN, tradename, manufacturedby Kyoeisha Chemical Co., Ltd.), 50 parts by mass of tripropylene glycoldiacrylate (ARONIX M220, tradename, manufactured by Toagosei Co, Ltd.)and 3 parts by mass of benzophenone were mixed to obtain a uniform resinliquid C.

The color tone correcting layer formed as mentioned above was coatedwith the resin liquid C by a bar coater, and irradiated with ultravioletrays under the same condition as in Step (b) of Example 1 to form atransparent resin layer having a thickness of 0.2 mm without a tuck.

An antireflection layer was formed on the transparent resin layer in thesame manner as in Step (c) of Example 1 to obtain an optical film.

EXAMPLE 3

An optical film was produced in the same manner as in Example 1 exceptthat a photo-curable resin to form a transparent resin layer, having adifferent cure shrinkage ratio, was used.

First, a color tone correcting layer was formed in the same manner as inStep (a) of Example 1.

Then, in order to form a transparent resin layer, 80 parts by mass ofCH₂═CHOCH₂CH(OH)CH₂O(CH₂)₆OCH₂CH(OH)CH₂OCH═CH₂ (KAYARAD R-167,tradename, manufactured by Nippon Kayaku Co., Ltd.), 20 parts by mass ofCH₂═CHCO(OE)_(n)OΦCH₂ΦO(EO)_(m)COCH═CH₂, wherein E is a 1,2-ethylenegroup, Φ is a 1,4-phenylene group, n+m=4 (KAYARAD R-712, tradename,manufactured by Nippon Kayaku Co., Ltd.) and 3 parts by mass ofbenzophenone were mixed to obtain a uniform resin liquid D.

The color tone correcting layer formed as mentioned above was coatedwith the resin liquid D by a bar coater, and irradiated with ultravioletrays under the same condition as in Step (b) of Example 1, to form atransparent resin layer having a thickness of 0.2 mm without a tuck.

An antireflection layer was formed on the transparent resin layer in thesame manner as in Step (c) of Example 1 to obtain an optical film.

EXAMPLE 4

An optical film was produced in the same manner as in Example 1 exceptthat the laminating order was changed.

First, a resin liquid B was obtained in the same manner as in Step (b)of Example 1. A transparent substrate made of a polyethyleneterephthalate film having a thickness of 100 μm was coated with theresin liquid B by a bar coater, followed by irradiation with ultravioletrays under the same condition as in Step (b) of Example 1 to form atransparent resin layer having a thickness of 0.2 mm without a tuck.

On this resin layer, an interlayer and an antireflection layer wereformed in the same manner as in Step (c) of Example 1.

Then, in order to constitute a color tone correcting layer, a coloredlayer A were obtained in the same manner as in Step (a) of Example 1.

On the other side of the transparent substrate made of a polyethyleneterephthalate film opposite from the side on which the transparent resinlayer and the antireflection layer were formed, a color tone correctinglayer was formed in the same manner as in Step (a) of Example 1 toobtain an optical film.

EXAMPLE 5

An optical film was produced in the same manner as in Example 1 exceptthat the method of forming the transparent resin layer was changed.

First, a color tone correcting layer was formed in the same manner as inStep (a) of Example 1. The color tone correcting layer was coated with aresin liquid B prepared in the same condition as in Step (b) of Example1 by a bar coater, and a covering material made of a polyethyleneterephthalate film (thickness: 100 μm), one side of which not subjectedto an adhesion facilitating treatment, different from theabove-mentioned transparent substrate, was laminated thereon by using alaminator employing two rolls arranged to have a spacing of 400 μ, sothat the surface of the covering material not subjected to an adhesionfacilitating treatment was in contact with the surface coated with resinliquid B. Then, irradiation with ultraviolet rays with a dose of 700mj/cm² was carried out by a high pressure mercury lamp (120 mW/cm², thedistance from the light source to the irradiated plane: 150 mm, linespeed: 2.0 m/min) through the covering material, then the coveringmaterial was separated. As a result, a transparent resin layer having athickness of 0.2 mm, having no tuck and having high smoothness wasformed on the color tone correcting layer.

Then, an antireflection layer was formed on the transparent resin layerin the same manner as in Step (a) of Example 1 to obtain an opticalfilm.

EXAMPLE 6

An optical film was produced in the same manner as in Example 4 exceptthat the method of forming the transparent resin layer was changed.

First, a resin liquid B was obtained in the same manner as in Step (b)of Example 1. A transparent substrate made of a polyethyleneterephthalate film having a thickness of 100 μm was coated with theresin liquid B by a bar coater, and a covering material made of apolyethylene terephthalate film (thickness: 100 μm), one side of whichnot subjected to an adhesion facilitating treatment, different from thetransparent substrate, was laminated thereon by using a laminatoremploying two rolls arranged to have a spacing of 400 μ, so that thesurface not subjected to an adhesion facilitating treatment was incontact with the surface coated with the resin liquid B. Then,irradiation with ultraviolet rays with a dose of 700 mj/cm² was carriedout by a high pressure mercury lamp (120 mW/cm², the distance from thelight source to the irradiated plane: 150 mm, line speed: 2.0 m/min)through the covering material, then the covering material was separated.As a result, a transparent resin layer having a thickness of 0.2 mm,having no tuck and having high smoothness was formed on the transparentsubstrate.

Then, an interlayer and an antireflection layer were formed on thetransparent resin layer in the same manner as in Step (c) of Example 1.

A color tone correcting layer was formed on the other side of thetransparent substrate made of a polyethylene terephthalate film oppositefrom the side on which the transparent resin layer and theantireflection layer were formed, in the same manner as in Step (a) ofExample 1, to obtain an optical film.

COMPARATIVE EXAMPLE 1

An optical film was produced in the same manner as in Example 1 exceptthat no color tone correcting layer was formed, and a colorant wascontained in a transparent resin layer made of a photo-curable resinhaving a self-healing property.

First, 70 parts by mass of a non-yellowing type urethane acrylate(UF-8001, tradename, manufactured by Kyoeisha Chemical Co., Ltd.) and 30parts by mass of tripropylene glycol diacrylate (ARONIX M220, tradename,manufactured by Toagosei Co, Ltd.) were mixed to obtain a uniform resinliquid. To this resin liquid, 6 parts by mass of a red dye (RED MP-FW,tradename, manufactured by Avecia, Ltd.), 7 parts by mass of a blue dye(Blue AP-FW, tradename, manufactured by Avecia, Ltd.) and 3 parts bymass of benzophenone, per 100 parts by mass of the resin component wereadded and mixed to obtain a colored photo-curable resin liquid E.

A transparent substrate made of a polyethylene terephthalate film havinga thickness of 100 μm was coated with the colored photo-curable resinliquid E by a bar coater, followed by irradiation with ultraviolet raysunder the same condition as in Step (b) of Example 1, whereupon a tuckwas formed on the colored transparent resin layer and the curing was notsufficient. Then, irradiation with ultraviolet rays with a dose of 600mj/cm² was further carried out to form a colored transparent resin layerhaving a thickness of 0.2 mm without a tuck.

An antireflection layer was formed on the colored transparent resinlayer in the same manner as in Step (c) of Example 1 to obtain anoptical film.

COMPARATIVE EXAMPLE 2

An optical film was produced in the same manner as in Example 1 exceptthat a thermosetting urethane resin having a self-healing property wasused as a material for the transparent resin layer instead of thephoto-curable resin having a self-healing property.

Namely, a color tone correcting layer was formed in the same manner asin Step (a) of Example 1, and a transparent resin layer made of athermosetting polyurethane resin was formed by the following method.First, a blend composition as identified in Table 1 was heated at 80° C.for 3 hours for melting, and mixed by stirring to obtain a uniformliquid I. Separately, a blend composition as identified in Table 2 washeated at 80° C. for 3 hours for melting, and mixed by stirring toobtain a uniform liquid II. The liquid I and the liquid II were mixedwith a mass ratio of 40:60. Then, the color tone correcting layer formedas mentioned above was coated with the mixture of the liquid I and theliquid II by a bar coater, and made to pass through an oven having itstemperature adjusted to 120° C. for 10 minutes to complete a reaction ofthe liquid I with the liquid II. Then, curing was carried out in an ovenhaving its temperature adjusted to 60° C. for 15 hours to form atransparent resin layer having a thickness of 0.2 mm.

An antireflection layer was formed on the transparent resin layer in thesame manner as in Step (c) of Example 1 to form an optical film.

TABLE 1 Liquid I Polycaprolactonetriol with a 78.2 parts by masshydroxyl value of 196.4 Polycaprolactonetriol with a 19.6 parts by masshydroxyl value of 540.3 Silicone type extender *1  0.5 part by massAntioxidant *2  0.5 part by mass Ultraviolet ray absorbent *3  0.7 partby mass Light stabilizer *4  0.5 part by mass *1 BYK-300, tradename,manufactured by Byk-Chemie Japan K.K. *2 IRGANOX 1010, tradename,manufactured by Ciba-Geigy *3 TINUVIN 328, tradename, manufactured byCiba-Geigy *4 MARK LA-77, tradename, manufactured by Asahi Denka KogyoK.K.

TABLE 2 Liquid II Isocyanurate-modified   100 parts by masshexamethyleneisocyanate having an isocyanate group content of 21.4%Dibuthyltin dilaurate 0.001 part by massEvaluation of Optical Film

With respect to the optical film obtained in each of above-mentionedExamples, an increase of the haze value was measured in order toevaluate scratch resistance.

The increase of the haze value is used as an index of the scratchresistance and is “a value (%) expressed by {(a haze value afterabrasion test)−(a haze value before abrasion test)} when a Taberabrasion test was carried out by employing CS-10F as truck wheels undera load of 500 g at 23° C. under a relative humidity of 50% for 100cycles”. With regard to an optical film, there is no problem if the hazevalue increase is at most 3%.

The measurement results of the haze value increase are shown in Table 3.The measurement of the haze value was carried out at four points on theabrasion cycle track, and the average value was calculated.

With respect to the optical film obtained in each of the above-mentionedExamples, deterioration of the colorant was evaluated by a method asfollows. Immediately after the formation of the color tone correctinglayer, and immediately after the formation of the transparent resinlayer, a spectral transmittance was measured by a spectrophotometer toobtain the difference in the transmittance. As the deterioration of thecolorant by ultraviolet ray irradiation develops, the difference in thetransmittance increases. The results are shown in Table 3.

Further, in each of the above-mentioned Examples, the density of thetransparent resin layer was measured before and after the curing of thetransparent resin layer, and the cure shrinkage ratio was calculated.The results are shown in Table 3.

Further, a self-healing degree of the transparent resin layer wasmeasured in each of the above-mentioned Examples. The results are shownin Table 3.

In Table 3, the transmittance of the optical film obtained in each ofthe above-mentioned Examples, and the dose of ultraviolet rayirradiation (UV irradiation dose) at the time of forming the transparentresin layer are also shown.

TABLE 3 Evaluation of Evaluation of transparent resin optical film layerScratch UV Evaluation of resistance Self- irradiation Cure colorantReflec- (Haze value healing dose shrinkage Difference in tance increase)property (mj/cm2) ratio transmittance Example 1 0.5% 1.2% 100 g 600 6%2% Example 2 0.5% 1.5%  95 g 600 7% 2% Example 3 0.5% 1.2% 100 g 60010%  2% Example 4 0.5% 1.2% 100 g 600 6% 2% Example 5 0.4% 1.2% 100 g700 6% 2% Example 6 0.4% 1.2% 100 g 700 6% 2% Comparative 0.5% 1.3% 100g 1200 6% 14%  Example 1 Comparative 0.5% 1.2% 100 g — 5% 6% Example 2

As shown in Table 3, the reflectance and scratch resistance of theoptical film were good in all Examples. In Comparative Example 1, alarge amount of ultraviolet ray irradiation was required to cure thetransparent resin layer, and the deterioration of the colorant wassignificant. In Comparative Example 2 wherein a thermosetting urethaneresin was used, not only it took very long time to form the transparentresin layer, but the deterioration of the colorant was also significant.

As described above, according to the present invention, an optical filmhaving an antireflection property and having an optical correctingproperty such as near infrared ray absorption or color tone correctionof visible light can be obtained with good productivity.

The entire disclosure of Japanese Patent Application No. 2001-191632filed on Jun. 25, 2001 including specification, claims, drawing andsummary are incorporated herein by reference in its entirety.

1. An optical film which comprises a transparent resin layer (1) made ofa photocured photo-curable urethane resin having a self-healingproperty, an antireflection layer (2) present on one side of thetransparent resin layer (1) and having a thickness of from 10 to 500 nm,and a color tone correcting layer (3) containing a colorant which has acolor tone correcting property, present on the other side of thetransparent resin layer (1) opposite from the antireflection layer (2).2. The optical film according to claim 1, wherein the antireflectionlayer (2) is made of a non-crystalline fluoropolymer.
 3. The opticalfilm according to claim 2, wherein the color tone correcting layer (3)further contains a colorant which has a near infrared ray absorptionproperty.
 4. The optical film according to claim 3, wherein thenon-crystalline fluoropolymer is a polymer having a fluorine-containingalicyclic structure.
 5. The optical film according to claim 2, whereinthe non-crystalline fluoropolymer is a polymer having afluorine-containing alicyclic structure.
 6. The optical film accordingto claim 1, wherein the color tone correcting layer (3) further containsa colorant which has a near infrared ray absorption property.
 7. Animage display device comprising the optical film according to claim 1,wherein the optical film is present on a display surface thereof.
 8. Theoptical film according to claim 1, wherein the self-healing property ofthe transparent resin layer is a value of at least 30 g measured as themaximum load measured by a HEIDON scratch tester, with which scratchesformed with a diamond chip scratcher having a tip diameter of 15 μm candisappear at 23° C. and a relative humidity of 50%.
 9. The optical filmaccording to claim 1, wherein the transparent resin layer is obtained byphotocuring a photo-curable resin composition on the color tonecorrecting layer.
 10. An optical film which comprises a transparentresin layer (1) made of a photocured photo-curable urethane resin havinga self-healing property, an antireflection layer (2) present on one sideof the transparent resin layer (1) and having a thickness from 10 to 500nm, and a color tone correcting layer (3) containing a colorant whichhas a color tone correcting property, present on the other side of thetransparent resin layer (1) opposite from the antireflection layer (2),wherein an interlayer having a refractive index higher than that of thetransparent resin layer (1), is present between the transparent resinlayer (1) and the antireflection layer (2).
 11. The optical filmaccording to claim 10, wherein the antireflection layer (2) is made of anon-crystalline fluoropolymer.
 12. The optical film according to claim11, wherein the color tone correcting layer (3) further contains acolorant which has a near infrared ray absorption property.
 13. Theoptical film according to claim 12, wherein the non-crystallinefluoropolymer is a polymer having a fluorine-containing alicyclicstructure.
 14. The optical film according to claim 11, wherein thenon-crystalline fluoropolymer is a polymer having a fluorine-containingalicyclic structure.
 15. The optical film according to claim 10, whereinthe color tone correcting layer (3) further contains a colorant whichhas a near infrared ray absorption property.
 16. The optical filmaccording to claim 10, wherein the self-healing property of thetransparent resin layer is a value of at least 30 g measured as themaximum load measured by a HEIDON scratch tester, with which scratchesformed with a diamond chip scratcher having a tip diameter of 15 μm candisappear at 23° C. and a relative humidity of 50%.
 17. The optical filmaccording to claim 10, wherein the first layer is obtained byphotocuring a photo-curable resin composition on the color tonecorrecting layer.